Green Peach Aphid and Black Peach Aphid (Aphids)
General Description
Hosts
Green peach and black peach aphids mainly attack peach; however, apricot, plum, cherry and other trees may be attacked. Green peach aphid also attacks a wide variety of vegetable and floricultural crops.
Damage
Green peach aphid - infestations on blossoms and new shoots cause flowers and leaves to curl tightly and shoots to stop growing (Fig. 1). Fruitlets may not develop or may drop; young peaches may be deformed and nectarines may be deformed and streaked with russet.
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| Figures 1 & 2. Leaves infested with green peach aphids. (H. Philip) | |
Black peach aphid – main damage is slowing growth of young trees and predisposing to attack by other insects and diseases and to damage by harsh weather conditions. Early summer above ground damage similar to green peach aphid. Sooty mold may develop where excessive honeydew is deposited on the fruit.
Identification
Eggs – oval, shiny black.
Nymph – Green peach aphid nymphs resemble wingless adults in colour but are smaller (Fig. 3); black peach aphid nymphs are reddish-brown.
Adult – Green peach aphid: wingless forms are light green to yellow; winged forms are pale to dark green with a large dusky blotch on the abdomen (Fig. 3).
Black peach aphid: both wingless and winged forms are shiny black in colour.
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| Figure 3. Colony of green peach aphids. (H. Philip) |
Life History
Green peach aphid - overwinters as eggs on host trees, especially peach. Eggs hatch well before leaf bud burst; nymphs attack blossoms then growing shoots and leaves. After 2-3 generations, winged forms emigrate in June to produce several generations on summer hosts. In the fall, winged forms return to the spring hosts to lay overwintering eggs.
Black peach aphid – overwinters as wingless adults on roots of host trees. Some adults move up trees to establish colonies on leaves and shoots which usually disappear by midsummer. After several generations, winged adults fly to new host trees. Aphid colonies are present year round on roots of host trees.
Monitoring
Inspect trees before bud burst for aphids on emerging leaves.
Management
Biological Control
Preserve the many predatory insects that feed on aphids by avoiding use of harmful chemicals where possible.
Chemical Control
Recommended timings and products:
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Husk fall - Admire, Alias, Beleaf, Closer, Exirel, Vayego 200SC and Sivanto Prime
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Summer - Admire, Alias, Clutch, Closer, Beleaf, Movento, Purespray Green Spray Oil 13E, Exirel, Sivanto Prime, Vayego 200SC and TwinGuard
Do not apply Admire or Alias more than 2 times per season, and only after bees are no longer foraging in the orchard. Movento should be applied in combination with a recommended non-ionic adjuvant (e.g. Agral 90). Do not tank mix Exirel with Flint, Pristine, Cabrio, Copper or Captan fungicides. Do not use Purespray Green Spray Oil 13E within 14 days before or after captan or sulphur applications. Dormant oil application before bud burst still provides adequate control when applied in sufficient water to ensure thorough coverage. Sprays applied for green peach aphid will also control black peach aphid.
Pesticide Resistance Management - Green peach aphid has developed resistance to most products in the past. Therefore it is important to alternate applications between products with different Group Numbers to avoid development of resistance to any chemical group.